[John Byrns]

In article ,
"Arny Krueger" wrote:

"John Byrns" wrote in message

In article ,
Eeyore wrote:

Trevor Wilson wrote:

High fidelity meaning with great accuracy. NOT with high
distortion.


**Because any product which DELIBERATELY introduces
(audible) distortion is, by definition, not high
fidelity. It is something else.

Exactly so. 'High fidelity' has a specific meaning that
specifically excludes adding intentional and entirely
avoidable distortions..

What is the relevance of "High fidelity" in today's audio
scene?

The search for accuracy made it everything good that it is.

Most, if not all, current recordings fail the
"High fidelity" test because of all the equalization,
compression, clipping, and etc. applied to them, along
with the microphone techniques used.

There's a lot of stuff, particularly in the classical domain, that is
recorded with a few mics and that's about it.

However, accurate reproduction of highly-produced recordings gets you closer
to what the producers intended.

I would think that to get the sound the producers intended, you would
not want an "accurate" system, you would want a reproducing system
identical in its effects to the one they used while producing the
recording, and even that wouldn't work if others made changes later, as
in the CD "mastering" process.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Tynan AgviÐr]

BTW: The claims made for Shakti Stones are not interesting at all.
They're just stupid.


Speaking of Shakti Stones and things of the Ilk, I was recently sent a
sample of .P.W.B *Rainbow Electret Foil*...a product, that when cut into
strips and applied to cds, sacds, vinyl, or cassette tapes, apparently
greatly improves the sound. of course I did it, and now not only is there
no sound improvement, (of course there isnt, Tynan, you dumbass), some of
the CDs wont even play
har.

look up PWB electronics, england.
http://www.belt.demon.co.uk/product/ref/ref.html

I DO greatly admire the audiophool's desire for better sound, and wish that
Professional sound engineers(or should I say the fat guys in suits behind
the record labels ) had as much of a drive to improve audio quality and not
just convenience/price/size... (I also wish that the audiophiles had just a
touch of sense to go with that ambition and could avoid Kool Aid, PCP, and
binges of ye old glass dick for a change)

[Iain Churches[_2_]]

"mick" wrote in message
.uk...

The term "high fidelity" really means "a high degree of truthfulness".

Indeed, that is the only accurate definition.

If you compare the final sound with the original performance (case 1)
then I completely agree, current recordings already fail the test before
the listener gets them.

As pointed out previously, if the recorfing has been put together
track by track, brick by brick, there*is* no original performance.

Alternatively, if you compare the recorded CD
with the final sound (case 2), then it passes - as the aim is to
reproduce the *cd's content* accurately.

IMHO only case 1 can be construed to be a test of "high fidelity".
Case 2 is really a test of accuracy of the reproducing equipment.

In case 1, when listening to most recordings, I can't see anything wrong
with modifying the final sound to suit the preferences of the listener.
As any pretence of "fidelity" has already been removed at the early
stages it no longer matters. This, for me, is the realm of SETs.

It can be applied also to amplifiers, cartridges and also speakers.
The listener picks the combination which he/she finds pleasing.
Accuracy (and therefore by definition hi-fidelity) is not generally
the among the pricipal criteria.

Case 2 requires accurate equipment. I couldn't really agree with anyone
who suggested SETs here. You really need "a piece of wire with gain" -
and no tone controls or anything else that would change the original
recording characteristics - even if they were a mess. I think TW and
Graham only recognise class2... ;-)

Perhaps the term "hi-fi" is indeed now redundant?

Yes. I think putting together a system to their taste
and budget which pleases their ear, is probably now the
requirement for most people.

Iain

[Iain Churches[_2_]]

"Arny Krueger" wrote in message
. ..
"John Byrns" wrote in message

In article ,
Eeyore wrote:

Trevor Wilson wrote:

High fidelity meaning with great accuracy. NOT with high
distortion.


**Because any product which DELIBERATELY introduces
(audible) distortion is, by definition, not high
fidelity. It is something else.

Exactly so. 'High fidelity' has a specific meaning that
specifically excludes adding intentional and entirely
avoidable distortions..

What is the relevance of "High fidelity" in today's audio
scene?

The search for accuracy made it everything good that it is.

Most, if not all, current recordings fail the
"High fidelity" test because of all the equalization,
compression, clipping, and etc. applied to them, along
with the microphone techniques used.

There's a lot of stuff, particularly in the classical domain, that is
recorded with a few mics and that's about it.

Indeed Arny. You give the impression it is a lot simpler
than it actually is. Neither do you specify what you mean by
"a few mics". There are actually very few topologies using a few mics
that actually work well. In addition, they require considerable
skill and experience in placing to get the correct ratio of
orchestra to ambience etc.


However, accurate reproduction of highly-produced recordings gets you
closer to what the producers intended.


Hmm. I wonder, how can you know what the producer intended?
I can tell you, from having sat next to recording producers on more
sessions than I can remember, their intention was to record a
performance to do justice to the intentions of the composer,
the reproduction of which would give pleasure to the listener.

[Iain Churches[_2_]]

"John Byrns" wrote in message
...
In article ,
Eeyore wrote:

Trevor Wilson wrote:

High fidelity meaning with great accuracy. NOT with high distortion.


**Because any product which DELIBERATELY introduces (audible)
distortion is,
by definition, not high fidelity. It is something else.

Exactly so. 'High fidelity' has a specific meaning that specifically
excludes
adding intentional and entirely avoidable distortions..

What is the relevance of "High fidelity" in today's audio scene? Most,
if not all, current recordings fail the "High fidelity" test because of
all the equalization, compression, clipping, and etc. applied to them,
along with the microphone techniques used.


I agree. It's relevance is now probably minimal.
People buy the combination of amplifier and speakers
which in their opinion works well in their room and
gives them a pleasing listening experience. This has
nothing to do with "high-fidelity in the strictest sense
of the word.

While I would agree with your comments re EQ,
compression etc as far as pop music goes, it certainly
does not (and never has) applied to classical music,
or to a great extent jazz. In classical recording the
well-informed choice of type and placement of
microphones make EQ almost unnecessary. In pop music,
sound shaping, and a lot more, is common practice. Try to
record a drum kit, multi-microphone without EQ, gates
and compressors and you will understand what I mean.
And before you say, "I would only use two mics" remember
that you cannot possibly achieve the presence, definition
the impact required with that technique.

The expectations of a pop audience (who probably listen
mainly in their cars, or with iPod, are very
different to those who enjoy classical music..

Best regards

Iain

[Iain Churches[_2_]]

"John Byrns" wrote in message
...
In article ,
"Iain Churches" wrote:

"John Byrns" wrote in message
...
In article ,
"Iain Churches" wrote:

was matched.
The BBC did this too (see Morgan Jones, Valve Amplifier 2nd Ed.page
452)
I was hoping that Graham would explain why this would have been done.

Did the BBC prefer this impedance level for speakers? For example I
see
that the LS3/4 monitoring speaker is 25 Ohms.

Yes it seems so. I am interested to know why.
I made the erroneous (?) assumption that better
damping was the objective.

Assuming that it was an erroneous assumption, only you can tell us why
you made it?

I thought (hoped) that Zo would remain the same, and so
the ratio of speaker to amplifier impedance might be greatly
improved.


Another thought is that" in the thinking of the time it
may have had to do with minimizing the interaction between the speakers
and the speaker "cables.

Possibly. Sadly, there are few designers left from that era that we can ask.

One somtimes sees BBC spec Leak amps for sale, which have
become separated from the speakers they were designed to drive.
People buy them in auction without realising that they have custom
OPTs.

I doubt it, this is simply an example of Graham opening his mouth
before
putting his brain fully in gear. "Norton/Thevenin equivalent ciruit
analyis" is of little relevance in understanding the reality of speaker
damping and the so called "damping factor.

Still, it would be of interest to have some discussion on this
point. It seems to be one of the stumbling blocks of understanding
in tube amps. I get the impression that Graham seems to think it
is unimportant in the greater scheme of things. He may well be right.
But if so, why do SS designers seem to attch so much importance
to Zo, and criticise poor damping factor as being one of the major
short comings of SET?

I don't have a clue why SS designers attach such importance to the so
called "damping factor".

Neither do I. But I am sure there is someone here who can tell us.

I assume it is because it is a simple number
that has been sold to the public and makes for good advertising copy.
With any reasonable "damping factor", of say 10 or better, the DC
resistance of the speaker voice coil completely dominates in determining
the electrical damping of the speaker, but this is a subtle point that
people don't' easily understand.

So you think that Zo = 0.8 Ohm is OK?

Tests by Olson, or was it Tremaine, showed that people were
unable to detect an increase in DF above 12 so your figure
may well be very close to the mark.

Iain

[Iain Churches[_2_]]

"Arny Krueger" wrote in message
...
"mick" wrote in message
.uk

As you point out, there are different "flavours" of sound
which appeal to different people. So what's wrong with
calling *almost anything* (including SET) "hi-fi"? After
all, it's just another "flavour"

Yes, let's face it - the prototypical 1950s 5-tube AC-DC radio with hot
chassis and cheap 4" speaker in a resonant plastic box is just another
"flavour". ;-)

and is just as close to
reality as the performance that was finally recorded.

Nope. There's no way you can show logically that a strategy of adding
randomly-chosen noise and distortion gets you closer to the original live
performance.

But that's the whole point, Arny, with the exception of classical
and jazz recordings, there is no *live* performance. Popular music
is assembled track by track (we call it musical brick-laying) Tracks
are added in different acoustics in studio which may be continents
apart. There is no *original* So, (and this is the crux of the
whole matter) people are looking for a system "which interprets
the music of their choice in a manner which pleases them" This
has nothing whatsoever to do with hi-fidelity or a non-existing
live performance.

Talk to people. Ask them the reason for the choice of the
amplifier and speakers they are using.

Sure, there's some horrible things being done to some recordings. But,
that was true in the 50s and 60s. Only then there was not as many viable
choices to do things right.

In the 50's and 60s the problems were different, and the level of
skill required much greater to make a good sounding record. It's
a lot easier these days (I know, I did it in the late 60s and do it
now:-)

Interesting discussion.

Iain

[John Byrns]

In article i,
"Iain Churches" wrote:

"John Byrns" wrote in message
...
In article ,
"Iain Churches" wrote:

"John Byrns" wrote in message
...
In article ,
"Iain Churches" wrote:

was matched.
The BBC did this too (see Morgan Jones, Valve Amplifier 2nd Ed.page
452)
I was hoping that Graham would explain why this would have been done.

Did the BBC prefer this impedance level for speakers? For example I
see
that the LS3/4 monitoring speaker is 25 Ohms.

Yes it seems so. I am interested to know why.
I made the erroneous (?) assumption that better
damping was the objective.

Assuming that it was an erroneous assumption, only you can tell us why
you made it?

I thought (hoped) that Zo would remain the same, and so
the ratio of speaker to amplifier impedance might be greatly
improved.

I seem to have misread your original paragraph, missing the period at
the end of the first line so that I thought you were interested in
knowing why you may have made a possibly erroneous assumption, rather
than why the BBC liked 25 Ohm speaker systems. Oh well, no great harm
seems to have been done although we are still left wondering about the
reasons for their choice of impedance.

The Zo of course changes because the turns ratio of the amplifier's
output transformer is changed to optimize amplifier's performance when
the load impedance is changed.

Another thought is that" in the thinking of the time it
may have had to do with minimizing the interaction between the speakers
and the speaker "cables.

Possibly. Sadly, there are few designers left from that era that we can ask.

One somtimes sees BBC spec Leak amps for sale, which have
become separated from the speakers they were designed to drive.
People buy them in auction without realising that they have custom
OPTs.

I doubt it, this is simply an example of Graham opening his mouth
before
putting his brain fully in gear. "Norton/Thevenin equivalent ciruit
analyis" is of little relevance in understanding the reality of speaker
damping and the so called "damping factor.

Still, it would be of interest to have some discussion on this
point. It seems to be one of the stumbling blocks of understanding
in tube amps. I get the impression that Graham seems to think it
is unimportant in the greater scheme of things. He may well be right.
But if so, why do SS designers seem to attch so much importance
to Zo, and criticise poor damping factor as being one of the major
short comings of SET?

I don't have a clue why SS designers attach such importance to the so
called "damping factor".

Neither do I. But I am sure there is someone here who can tell us.

We can always hope, but I doubt it is likely to be explained in a
reasonable way.

I assume it is because it is a simple number
that has been sold to the public and makes for good advertising copy.
With any reasonable "damping factor", of say 10 or better, the DC
resistance of the speaker voice coil completely dominates in determining
the electrical damping of the speaker, but this is a subtle point that
people don't' easily understand.

So you think that Zo = 0.8 Ohm is OK?

Yes, after that the effect of Zo on electrical damping of the speaker is
completely swamped by the DC resistance of the speakers VC and xover
network.

Tests by Olson, or was it Tremaine, showed that people were
unable to detect an increase in DF above 12 so your figure
may well be very close to the mark.

That's not at all surprising and does not reflect negatively on people's
hearing acuity. It is simply a result of changes in Zo beyond a certain
point being completely swamped by the speakers DC resistance as far as
the electrical damping of the speaker goes.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Iain Churches[_2_]]

"John Byrns" wrote in message
...
In article i,
"Iain Churches" wrote:

JB wrote
I don't have a clue why SS designers attach such importance to the so
called "damping factor".

Iain replied
Neither do I. But I am sure there is someone here who can tell us.

We can always hope, but I doubt it is likely to be explained in a
reasonable way.

perhaps Graham, Trevor or someone else can help us out here.

So you think that Zo = 0.8 Ohm is OK?

Yes, after that the effect of Zo on electrical damping of the speaker is
completely swamped by the DC resistance of the speakers VC and xover
network.

Tests by Olson, or was it Tremaine, showed that people were
unable to detect an increase in DF above 12 so your figure
may well be very close to the mark.

That's not at all surprising and does not reflect negatively on people's
hearing acuity.

No of course not. I fact it is quite possible that the level of
aural perception in the pre .mp3/iPod days was higher. This
is certainly so regarding levels of expectation.

It is simply a result of changes in Zo beyond a certain
point being completely swamped by the speakers DC
r esistance as far as
the electrical damping of the speaker goes.

Tremaine makes an interesting statement that the correct
formula for calculating DF is in fact Zls/(Zout + Rvc) where
Zls is the impedance of the speaker, Zout is the internal
impedance of the amplifier, and Rvc is the DC resistance of
the voice coil.

Using the convential formula, Zout of 0.5 Ohms with a
speaker of 8 Ohms gives a DF of 16. Adding the voice
coil resistance the DF becomes 1.23, and even with Zout=0
the DF cannot rise above 1.33

Regards
Iain

[Tynan AgviÐr]

"Iain Churches" wrote in
i.fi:


"Eeyore" wrote in message
...


Iain Churches wrote:

"Arny Krueger" wrote in message
"Eeyore" wrote
Trevor Wilson wrote:

After some considerable effort, I placed the amplifiers
under the floor, directly beneath each speaker. The
improvement was even more pronounced.

If only more people would accept the concept of 'active
speakers' the nonsense with speaker cables could be
entirely eliminated.

The requirement of two cables per speaker, and surrendering
amplifier choice are problems for most audiophiles.

For example, Paradigm developed and marketed some very credible
powered speakers, and dropped them for lack of interest.

Hi Arny.

The Finnish manufacturer Genelec has a very successful range of
active loudspeakers designed for both domestic and studio
environments. One sees them often in the UK, and of course in
Scandinavia.

http://www.genelec.com/

They are well represented in the US.
GENELEC Inc. - 7 Tech Circle - Natick - MA 01760 - USA -
Tel +1 508 652 0900 - Fax +1 508 652 0909 -
Email

Give them a listen if you get the chance. I don't think you
will be disappointed.

Genelecs have reputation of sounding excessively 'forward' sadly.
Presumably
a 'pronounced' mid-range is to blame.

Maybe they feel they sell more speakers that way ? Who can tell why
they do
it.


It's a question of taste. Maybe a forward sounding sound
stage is flattering for some clients/projects. They seem to
be a popular choice with UK studios.

Personally, I am stuck on Tannoys and B+W 801D
To each his own:-)

Iain




I use 802s, Link Audio k100s, and Von Schweikert VR-4 SRs.

Unfortunately, the vast majority of "studio monitors" sound like dog ass,
and are not good for doing audio work(or listening, for that matter)..so
I purchase products aimed at the HiFi market instead, and get better
results to these ears(though I do use a single Auratone)

[Eeyore]

"Tynan AgviÐr" wrote:

Unfortunately, the vast majority of "studio monitors" sound like dog ass,
and are not good for doing audio work(or listening, for that matter)..so
I purchase products aimed at the HiFi market instead, and get better
results to these ears(though I do use a single Auratone)

May I suggest you audition some PMCs ?
http://www.pmc-speakers.com/

I was most impressed.

Graham

[Iain Churches[_2_]]

"Tynan AgviÐr" wrote in message
. 3.70...

Iain wrote
It's a question of taste. Maybe a forward sounding sound
stage is flattering for some clients/projects. They seem to
be a popular choice with UK studios.

Personally, I am stuck on Tannoys and B+W 801D
To each his own:-)


I use 802s, Link Audio k100s, and Von Schweikert VR-4 SRs.

I would be interested to know which speaker you use for
which each of the types of project you mentioned.

You will find that when and if you work for discerning clients,
you will have to be able to offer monitoring options. Many clients
are fairly set in their ways. They will not expect to see domstic speakers.

Unfortunately, the vast majority of "studio monitors" sound like dog ass,
and are not good for doing audio work(or listening, for that matter)..so
I purchase products aimed at the HiFi market instead, and get better
results to these ears(though I do use a single Auratone)'

Hmm. I wonder if you really have enough experience to make such
a statement. Check the inlay booklets on classical CDs. You will find
that that a large number of the most highly regarded labels give technical
credit to B+W or Tannoy.

Auratone? Now there's a name from the past:-) I have a a pair of
Auratone wedges on my bench. Fine for close field monitoring for
TV commercials etc, but useless for music recording.

Iain

[Trevor Wilson[_2_]]

"Iain Churches" wrote in message
ti.fi...

"Trevor Wilson" wrote in message
...

"Iain Churches" wrote in message
ti.fi...


Precisely. These are people with whom you are in mutual
disagreement on the subject of SET.

**Yep. And I'll state it again: I do not call people who dissagree with
me
deluded morons. Just SET proponents.

One and the same thing.

**Not by a long chalk. Graham and I dissagree about the use of NFB in
amplifiers. I do not call him deluded. Many people dissagree about my
preference for SS amplification, over (PP) valve amplification. I do not
call them deluded. Just SET proponents.


**People who argue that SET amplifiers have any place in a high
fidelity
system are already arguing from a position of extreme ignorance. So,
no.


People don't seem to concerned about what can or cannot
be termed hi-fidelity.

**I see. And what gives YOU the right to speak for "people"?

What they are concerned about is the
emotional experience, the degree of listening pleasure if you
like, which they get from a particular system. This becomes
the main criterion for their choice.

**I am not arguing personal preference. I am arguing against the use of SET
amplification in a high fidelity system.


They may wonder why you cannot enjoy the emotional
musical experience that they do.

**Non-sequitur. You do not know that I do not enjoy music.

I would be interested to hear of your musical experiences
as a listener.

**As well you might be. After you start treating me with a little respect, I
may decide to tell you of my personal feeling about such things.


Have you considered that?

**Have you considered that you are an idiot, for asking a stupid
question,
without ascertaining the facts first?

There you go again, and you accuse *me* of being
insulting:-)

**You asked the stupid question. YOU started insuting me. YOU refused to
apologise for doing so. Reap what you sow, Mr Churches.



I greatly prefer the sound of the Decca style of recording to
that of say Sony Classical, as I find the Decca acoustical
interpretation, if I can call it that, to be more to my taste.
However, what I do not say is: "Decca is better, more
accurate. Those who don't agree are morons" Such an
attitude can never lead to rational discussion"

**The production style of a recording is part of the artistic side of the
music. I do not quibble with matters of artistry.

Read my paragraph again. I did not once use the word
"production" I talk about recording style and acoustical
interpretation, which is solely to do with the choice of
recording location, and the choice and placement of
microphone etc Perhaps these are not areas of
expertise which are familiar to you. They are my
speciality.

**Placement of microphones, different halls, different conductors and
different musicians, are all part of the differences in production.



I have my opinions. I like
my Decca version of Also Sprach Zarathustra (Zubin Mehta), but find the
Deutsche Grammophon version (Von Karajan) unlistenable. Others may
dispute this and they are entitled to their opinion. However, we are not
discussing matters of artistic variety.

Indeed we are not. You have completely missed the point.

**Nope. Mehta and Karajan have very different artistic interpretations of
the same piece of music. That is part of what provides artistic variety. If
the listener adds distortion, then that removes some of what the artists
orginally intended.



We are discussing a music REPRODUCTION system. It is not a music
PRODUCTION system. Much of the music I listen to has made it's way
through
equipment which exhibits high levels of distortion. That is the choice of
the artists. Who am I to decide how their music should be listened to?
Using deliberate distortion-creating products (like SETs) perverts the
intent of the artist/s.

I agree entirely with your comments about excess distortion,
but you have yet to convince me, or anyone else it seems, that the
very low distortion (typically 0.1%) produced by a SET with speakers
of SPL 100 or so, is even discernible.

**And AGAIN, you miss the point. THD is just ONE problem with SET
amplifiers. SET amplifiers exhibit a range of linear and non-linear (THD and
IMD) distortions. The frequency response errors are the most critically
problematical areas of SET amplifiers, UNLESS they happen to be operating
into a resistive load. I've explained this to you many, many times before.
Why do you continually ignore this point and focus almost solely on THD? Why
do you ignore, for instance, the quite audible frequency response variations
caused by using a SET amp into a pair of real-life loudspeakers?


I respect you right to your opinion,

**No, you do not. This would be yet, another, of your long list of lies.

Try, Trevor, just for once, to have some sense of decorum
and discuss this like a rational adult.

**Sure. Apologise for your past insults and I will believe what you say.



but sadly, as long
as you insist on behaving like a pre-adolescent child,

**I respond precisely to your contuned insults in the way you deserve.


I wouldthink that the chances of anyone coming
forward to discuss this matter with you are slim
to none.

**Of course. There is no place for SETs in a high fidelity system. They
are indefensible.

Once again, I respect your opinion.

**No, you do not. You are unable to argue reationally and logically, so you
resort to insult. You do so, with monotonous regularity.

Some would not agree
with you. You must allow them the freedom of their views.

**If a SET proponent claims his/her product has High Fidelity pretensions,
then he/she needs to prove it. If a SET proponent simply claims that they
PREFER the sound of their SET amp, then who am I to argue their choice?


In contrast, in the last few days there has been quite a
lot of interesting e-mail discussion, based on what has
been written here.

**So?

The fact that you have not been included in this could
perhaps indicate how little your opinion is valued.

**My opinions are not valued at the hospital for the criminally insane
either. I lose no sleep over that either. I don't care about anyone's
delusions. I only care about the propmotion of those delusions as if they
were some kind of truth.

There is no discussing with your kind of immature
adamancy. People must be allowed the freedom of
choice.

**I'm not interfering with anyone's freedom of choice. I am challenging the
delusions of some people. Nothing more.

It is them interesting to discuss with them the
criteria involved in that choice.

**Yeah, sure. Real interesting.

Trevor Wilson

[John Byrns]

In article ,
"Trevor Wilson" wrote:

**Not by a long chalk. Graham and I dissagree about the use of NFB in
amplifiers.

I wouldn't have guessed in a million years that you and Graham disagree
about the use of NFB in amplifiers. Which one of you is on which side
of the issue?

**And AGAIN, you miss the point. THD is just ONE problem with SET
amplifiers. SET amplifiers exhibit a range of linear and non-linear (THD and
IMD) distortions. The frequency response errors are the most critically
problematical areas of SET amplifiers, UNLESS they happen to be operating
into a resistive load. I've explained this to you many, many times before.
Why do you continually ignore this point and focus almost solely on THD? Why
do you ignore, for instance, the quite audible frequency response variations
caused by using a SET amp into a pair of real-life loudspeakers?

I'm new to this argument, can you explain it once for me, why a SET
amplifier should have worse frequency response variations than a PP
amplifier into a pair of real-life loudspeakers, assuming adequate OPT
inductance?


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Trevor Wilson[_2_]]

"John Byrns" wrote in message
...
In article ,
"Trevor Wilson" wrote:

**Not by a long chalk. Graham and I dissagree about the use of NFB in
amplifiers.

I wouldn't have guessed in a million years that you and Graham disagree
about the use of NFB in amplifiers. Which one of you is on which side
of the issue?

**I have a preference for zero global NFB. Graham prefers global NFB.


**And AGAIN, you miss the point. THD is just ONE problem with SET
amplifiers. SET amplifiers exhibit a range of linear and non-linear (THD
and
IMD) distortions. The frequency response errors are the most critically
problematical areas of SET amplifiers, UNLESS they happen to be operating
into a resistive load. I've explained this to you many, many times
before.
Why do you continually ignore this point and focus almost solely on THD?
Why
do you ignore, for instance, the quite audible frequency response
variations
caused by using a SET amp into a pair of real-life loudspeakers?

I'm new to this argument, can you explain it once for me, why a SET
amplifier should have worse frequency response variations than a PP
amplifier into a pair of real-life loudspeakers, assuming adequate OPT
inductance?

**SET amplifiers possess rather poor output impedance characteristics. More
critically, perhaps, is their inability to tolerate varying load impedances,
whilst maintaining an approximation of a Voltage source (which virtually all
loudspeakers require).

IOW: Anything a SE amplifier can do, a PP amp will do better, cheaper, more
efficiently and with lower distortion.

Trevor Wilson

[Eeyore]

Trevor Wilson wrote:

"John Byrns" wrote
"Trevor Wilson" wrote:

**Not by a long chalk. Graham and I dissagree about the use of NFB in
amplifiers.

I wouldn't have guessed in a million years that you and Graham disagree
about the use of NFB in amplifiers. Which one of you is on which side
of the issue?

**I have a preference for zero global NFB. Graham prefers global NFB.

It's about the ONLY way you can make the output impedance of a normally biased
bipolar output stage behave itself for one thing.

Emitter followers without loop-feedback aren't that great.

Graham

[John Byrns]

In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...
In article ,
"Trevor Wilson" wrote:

**Not by a long chalk. Graham and I dissagree about the use of NFB in
amplifiers.

I wouldn't have guessed in a million years that you and Graham disagree
about the use of NFB in amplifiers. Which one of you is on which side
of the issue?

**I have a preference for zero global NFB. Graham prefers global NFB.

Interesting given your preference for SS amplifiers, how many are there
that don't use global NFB?

**And AGAIN, you miss the point. THD is just ONE problem with SET
amplifiers. SET amplifiers exhibit a range of linear and non-linear (THD
and
IMD) distortions. The frequency response errors are the most critically
problematical areas of SET amplifiers, UNLESS they happen to be operating
into a resistive load. I've explained this to you many, many times
before.
Why do you continually ignore this point and focus almost solely on THD?
Why
do you ignore, for instance, the quite audible frequency response
variations
caused by using a SET amp into a pair of real-life loudspeakers?

I'm new to this argument, can you explain it once for me, why a SET
amplifier should have worse frequency response variations than a PP
amplifier into a pair of real-life loudspeakers, assuming adequate OPT
inductance?

**SET amplifiers possess rather poor output impedance characteristics. More
critically, perhaps, is their inability to tolerate varying load impedances,
whilst maintaining an approximation of a Voltage source (which virtually all
loudspeakers require).

How is this any different than an equivalent PP amplifier?

IOW: Anything a SE amplifier can do, a PP amp will do better, cheaper, more
efficiently and with lower distortion.

Most of that is true, but it is not true of there relative ability to
approximate a voltage source, assuming equivalent amplifiers, SE and PP
are pretty much the same in this regard.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[John Byrns]

In article i,
"Iain Churches" wrote:

Tremaine makes an interesting statement that the correct
formula for calculating DF is in fact Zls/(Zout + Rvc) where
Zls is the impedance of the speaker, Zout is the internal
impedance of the amplifier, and Rvc is the DC resistance of
the voice coil.

Using the convential formula, Zout of 0.5 Ohms with a
speaker of 8 Ohms gives a DF of 16. Adding the voice
coil resistance the DF becomes 1.23, and even with Zout=0
the DF cannot rise above 1.33

That all sounds reasonable, but I believe there are various other
factors that affect the electrical damping of the speaker, like for
example the strength of the magnetic field. In addition there is the
acoustic damping of the speaker, and even some mechanical damping. It's
enough to make the mind spin, no wonder they went for the simple minded
"damping factor".


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Eeyore]

John Byrns wrote:

"Trevor Wilson" wrote:
"John Byrns" wrote i
"Trevor Wilson" wrote:

**Not by a long chalk. Graham and I dissagree about the use of NFB in
amplifiers.

I wouldn't have guessed in a million years that you and Graham disagree
about the use of NFB in amplifiers. Which one of you is on which side
of the issue?

**I have a preference for zero global NFB. Graham prefers global NFB.

Interesting given your preference for SS amplifiers, how many are there
that don't use global NFB?

Almost none I should think.

Incidentally, I'm also a great fan of using local NFB too ( I like inherently
linear gain stages with good bandwidth ) with global NFB being the icing on the
cake.

Graham

[Trevor Wilson[_2_]]

"Eeyore" wrote in message
...


Trevor Wilson wrote:

"John Byrns" wrote
"Trevor Wilson" wrote:

**Not by a long chalk. Graham and I dissagree about the use of NFB in
amplifiers.

I wouldn't have guessed in a million years that you and Graham disagree
about the use of NFB in amplifiers. Which one of you is on which side
of the issue?

**I have a preference for zero global NFB. Graham prefers global NFB.

It's about the ONLY way you can make the output impedance of a normally
biased
bipolar output stage behave itself for one thing.

**Nope.


Emitter followers without loop-feedback aren't that great.

**Who said that a BJT amp required Emitter follower outputs?

Trevor Wilson

[Trevor Wilson[_2_]]

"John Byrns" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...
In article ,
"Trevor Wilson" wrote:

**Not by a long chalk. Graham and I dissagree about the use of NFB in
amplifiers.

I wouldn't have guessed in a million years that you and Graham disagree
about the use of NFB in amplifiers. Which one of you is on which side
of the issue?

**I have a preference for zero global NFB. Graham prefers global NFB.

Interesting given your preference for SS amplifiers, how many are there
that don't use global NFB?

**I don't know. 5, 10, 100, 1,000? Lots probably. It's all I have used for
the last 25 years.


**And AGAIN, you miss the point. THD is just ONE problem with SET
amplifiers. SET amplifiers exhibit a range of linear and non-linear
(THD
and
IMD) distortions. The frequency response errors are the most
critically
problematical areas of SET amplifiers, UNLESS they happen to be
operating
into a resistive load. I've explained this to you many, many times
before.
Why do you continually ignore this point and focus almost solely on
THD?
Why
do you ignore, for instance, the quite audible frequency response
variations
caused by using a SET amp into a pair of real-life loudspeakers?

I'm new to this argument, can you explain it once for me, why a SET
amplifier should have worse frequency response variations than a PP
amplifier into a pair of real-life loudspeakers, assuming adequate OPT
inductance?

**SET amplifiers possess rather poor output impedance characteristics.
More
critically, perhaps, is their inability to tolerate varying load
impedances,
whilst maintaining an approximation of a Voltage source (which virtually
all
loudspeakers require).

How is this any different than an equivalent PP amplifier?

**The load presented by a loudspeaker is not a resistor (in the vast
majority of cases). The impedance varies somewhat away from the 'nomimal'
impedance. Usually, that impedance falls below the nominal one. A SET
amplifier rated at (say) 10 Watts @ 8 Ohms, can only deliver a maximum of 5
Watts, when the impedance falls to 4 Ohms, 2.5 Watts @ 2 Ohms and so on. A
PP amp, OTOH, will almost always INCREASE it's power, as the load impedance
falls. IOW: It more closely approximates a Voltage source. The better the
amplifier, the more closely it approaches that ideal Voltage source. SET
amplifiers are the antithesis of this.


IOW: Anything a SE amplifier can do, a PP amp will do better, cheaper,
more
efficiently and with lower distortion.

Most of that is true, but it is not true of there relative ability to
approximate a voltage source, assuming equivalent amplifiers, SE and PP
are pretty much the same in this regard.

**No.

Trevor Wilson

[John Byrns]

In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...

How is this any different than an equivalent PP amplifier?

**The load presented by a loudspeaker is not a resistor (in the vast
majority of cases). The impedance varies somewhat away from the 'nomimal'
impedance. Usually, that impedance falls below the nominal one. A SET
amplifier rated at (say) 10 Watts @ 8 Ohms, can only deliver a maximum of 5
Watts, when the impedance falls to 4 Ohms, 2.5 Watts @ 2 Ohms and so on. A
PP amp, OTOH, will almost always INCREASE it's power, as the load impedance
falls. IOW: It more closely approximates a Voltage source.

You are making this assertion, but simply asserting it as you are doing
doesn't make it true. What is the basis for this supposed difference,
what is behind it from a theoretical perspective?


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Trevor Wilson[_2_]]

"John Byrns" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...

How is this any different than an equivalent PP amplifier?

**The load presented by a loudspeaker is not a resistor (in the vast
majority of cases). The impedance varies somewhat away from the 'nomimal'
impedance. Usually, that impedance falls below the nominal one. A SET
amplifier rated at (say) 10 Watts @ 8 Ohms, can only deliver a maximum of
5
Watts, when the impedance falls to 4 Ohms, 2.5 Watts @ 2 Ohms and so on.
A
PP amp, OTOH, will almost always INCREASE it's power, as the load
impedance
falls. IOW: It more closely approximates a Voltage source.

You are making this assertion, but simply asserting it as you are doing
doesn't make it true.

**I suggest you study up on the design and operation of SE amplification (it
doesn't matter if it is valve or transsistor). There is simply not enough
space for me to explain. It is a fact, not an assertion.

What is the basis for this supposed difference,
what is behind it from a theoretical perspective?

**Like I said: You'll need to study some good texts on the subject. Consider
what happens in a typical amplifier:

A Class A PP amp rated at (say) 10 Watts @ 8 Ohms could (theoretically)
deliver close to 20 Watts @ 4 Ohms, 40 Watts @ 2 Ohms and so on. Any power
level beyond 10 Watts will, however, be in Class A/B. A SE amplifier (be it
transistor or valve) cannot exceed it's maximum rated power @ it's rated
impedance. Not ever. Severe distortion is the result.

Trevor Wilson

[John Byrns]

In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...

How is this any different than an equivalent PP amplifier?

**The load presented by a loudspeaker is not a resistor (in the vast
majority of cases). The impedance varies somewhat away from the 'nomimal'
impedance. Usually, that impedance falls below the nominal one. A SET
amplifier rated at (say) 10 Watts @ 8 Ohms, can only deliver a maximum of
5
Watts, when the impedance falls to 4 Ohms, 2.5 Watts @ 2 Ohms and so on.
A
PP amp, OTOH, will almost always INCREASE it's power, as the load
impedance
falls. IOW: It more closely approximates a Voltage source.

You are making this assertion, but simply asserting it as you are doing
doesn't make it true.

**I suggest you study up on the design and operation of SE amplification (it
doesn't matter if it is valve or transsistor). There is simply not enough
space for me to explain. It is a fact, not an assertion.

In other words you don't have a clue what you are talking about and are
simply repeating a myth you heard somewhere.

What is the basis for this supposed difference,
what is behind it from a theoretical perspective?

**Like I said: You'll need to study some good texts on the subject. Consider
what happens in a typical amplifier:

A Class A PP amp rated at (say) 10 Watts @ 8 Ohms could (theoretically)
deliver close to 20 Watts @ 4 Ohms, 40 Watts @ 2 Ohms and so on. Any power
level beyond 10 Watts will, however, be in Class A/B. A SE amplifier (be it
transistor or valve) cannot exceed it's maximum rated power @ it's rated
impedance. Not ever. Severe distortion is the result.

I thought we were talking about source impedance, not whether a PP amp
might be able to deliver more than its rated power into a load lower
than its rated load impedance, a completely different matter?


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Trevor Wilson[_2_]]

"John Byrns" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...

How is this any different than an equivalent PP amplifier?

**The load presented by a loudspeaker is not a resistor (in the vast
majority of cases). The impedance varies somewhat away from the
'nomimal'
impedance. Usually, that impedance falls below the nominal one. A SET
amplifier rated at (say) 10 Watts @ 8 Ohms, can only deliver a maximum
of
5
Watts, when the impedance falls to 4 Ohms, 2.5 Watts @ 2 Ohms and so
on.
A
PP amp, OTOH, will almost always INCREASE it's power, as the load
impedance
falls. IOW: It more closely approximates a Voltage source.

You are making this assertion, but simply asserting it as you are doing
doesn't make it true.

**I suggest you study up on the design and operation of SE amplification
(it
doesn't matter if it is valve or transsistor). There is simply not enough
space for me to explain. It is a fact, not an assertion.

In other words you don't have a clue what you are talking about and are
simply repeating a myth you heard somewhere.

**I beg your pardon? Have you studied electronics? To what level? I don't
have the time nor the space to launch into a full dscription of what you
need to know. At some point, in these things, you need to do your own
homework. I studied electronics for 4 years. If you expect me to condense
several months study into a Usenet post, then you're in for a terrible
shock. It won't happen. Go buy the damned book. RDH4 is a good start for
valves. Doug Self's book is a good start for SS.


What is the basis for this supposed difference,
what is behind it from a theoretical perspective?

**Like I said: You'll need to study some good texts on the subject.
Consider
what happens in a typical amplifier:

A Class A PP amp rated at (say) 10 Watts @ 8 Ohms could (theoretically)
deliver close to 20 Watts @ 4 Ohms, 40 Watts @ 2 Ohms and so on. Any
power
level beyond 10 Watts will, however, be in Class A/B. A SE amplifier (be
it
transistor or valve) cannot exceed it's maximum rated power @ it's rated
impedance. Not ever. Severe distortion is the result.

I thought we were talking about source impedance, not whether a PP amp
might be able to deliver more than its rated power into a load lower
than its rated load impedance, a completely different matter?

**It's part of the problem with SE amplifiers. Unless you use perfectly
resistive loudspeakers. If you do, then that is not a problem.

Trevor Wilson

[John Byrns]

In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...

How is this any different than an equivalent PP amplifier?

**The load presented by a loudspeaker is not a resistor (in the vast
majority of cases). The impedance varies somewhat away from the
'nomimal'
impedance. Usually, that impedance falls below the nominal one. A SET
amplifier rated at (say) 10 Watts @ 8 Ohms, can only deliver a maximum
of
5
Watts, when the impedance falls to 4 Ohms, 2.5 Watts @ 2 Ohms and so
on.
A
PP amp, OTOH, will almost always INCREASE it's power, as the load
impedance
falls. IOW: It more closely approximates a Voltage source.

You are making this assertion, but simply asserting it as you are doing
doesn't make it true.

**I suggest you study up on the design and operation of SE amplification
(it
doesn't matter if it is valve or transsistor). There is simply not enough
space for me to explain. It is a fact, not an assertion.

In other words you don't have a clue what you are talking about and are
simply repeating a myth you heard somewhere.

**I beg your pardon? Have you studied electronics? To what level? I don't
have the time nor the space to launch into a full dscription of what you
need to know. At some point, in these things, you need to do your own
homework. I studied electronics for 4 years. If you expect me to condense
several months study into a Usenet post, then you're in for a terrible
shock. It won't happen. Go buy the damned book. RDH4 is a good start for
valves. Doug Self's book is a good start for SS.

If you had a clue what you were talking about, a few simple sentences
would be all that was needed to provide justification for your assertion
if it were true, but you clearly didn't learn much in your 4 year study
of electronics and you are simply trying to avoid the issue.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Eeyore]

Trevor Wilson wrote:

"Eeyore" wrote

Emitter followers without loop-feedback aren't that great.

**Who said that a BJT amp required Emitter follower outputs?

What do you propose in their place ?

Graham

[Eeyore]

John Byrns wrote:

"Trevor Wilson" wrote:
"John Byrns" wrote

How is this any different than an equivalent PP amplifier?

**The load presented by a loudspeaker is not a resistor (in the vast
majority of cases). The impedance varies somewhat away from the 'nomimal'
impedance. Usually, that impedance falls below the nominal one. A SET
amplifier rated at (say) 10 Watts @ 8 Ohms, can only deliver a maximum of 5
Watts, when the impedance falls to 4 Ohms, 2.5 Watts @ 2 Ohms and so on. A
PP amp, OTOH, will almost always INCREASE it's power, as the load impedance
falls. IOW: It more closely approximates a Voltage source.

You are making this assertion, but simply asserting it as you are doing
doesn't make it true. What is the basis for this supposed difference,
what is behind it from a theoretical perspective?

It comes from basic electrical power transfer theory.

Graham

[Eeyore]

John Byrns wrote:

I thought we were talking about source impedance, not whether a PP amp
might be able to deliver more than its rated power into a load lower
than its rated load impedance, a completely different matter?

No, they're intimately connected concepts.

Graham

[Eeyore]

John Byrns wrote:

"Trevor Wilson" wrote:
"John Byrns" wrote:

In other words you don't have a clue what you are talking about and are
simply repeating a myth you heard somewhere.

**I beg your pardon? Have you studied electronics? To what level? I don't
have the time nor the space to launch into a full dscription of what you
need to know. At some point, in these things, you need to do your own
homework. I studied electronics for 4 years. If you expect me to condense
several months study into a Usenet post, then you're in for a terrible
shock. It won't happen. Go buy the damned book. RDH4 is a good start for
valves. Doug Self's book is a good start for SS.

If you had a clue what you were talking about, a few simple sentences
would be all that was needed to provide justification for your assertion
if it were true,

You need to read up ELECTRICITY 101 to understand this. It's not even complicated
enough to warrant being called electronics.

Read about "power transfer" with respect to source and load resistances. There are
plenty of good examples using a battery to keep it simple.

Graham

[Patrick Turner]

Trevor Wilson wrote:

"John Byrns" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"John Byrns" wrote in message
...

How is this any different than an equivalent PP amplifier?

**The load presented by a loudspeaker is not a resistor (in the vast
majority of cases). The impedance varies somewhat away from the 'nomimal'
impedance. Usually, that impedance falls below the nominal one. A SET
amplifier rated at (say) 10 Watts @ 8 Ohms, can only deliver a maximum of
5
Watts, when the impedance falls to 4 Ohms, 2.5 Watts @ 2 Ohms and so on.
A
PP amp, OTOH, will almost always INCREASE it's power, as the load
impedance
falls. IOW: It more closely approximates a Voltage source.

You are making this assertion, but simply asserting it as you are doing
doesn't make it true.

**I suggest you study up on the design and operation of SE amplification (it
doesn't matter if it is valve or transsistor). There is simply not enough
space for me to explain. It is a fact, not an assertion.

What is the basis for this supposed difference,
what is behind it from a theoretical perspective?

**Like I said: You'll need to study some good texts on the subject. Consider
what happens in a typical amplifier:

A Class A PP amp rated at (say) 10 Watts @ 8 Ohms could (theoretically)
deliver close to 20 Watts @ 4 Ohms, 40 Watts @ 2 Ohms and so on. Any power
level beyond 10 Watts will, however, be in Class A/B. A SE amplifier (be it
transistor or valve) cannot exceed it's maximum rated power @ it's rated
impedance. Not ever. Severe distortion is the result.

Trevor Wilson

The reason a maker specifies that a 10 watt amp good for 10 watts into 8
ohms
is a 10 watt amp often means the amp won't like being run with 4 ohms,
and sure won't like 2 ohms, where theoretically 40 watts is possible.

The maker rating encourages ppl to use a sensible 8 ohm load.

( the PO will reduce due to voltage rail clipping if RL 8 ohms, BTW,
so trying to get high power into bass impedances is impossible. )

However, loads down to 2 ohms might easily be possible providing
speaker power is kept say below 2 watts continuous, and nothing is
clipping.

Teenagers and a 10 watt amp don't mix because they wanna turn it up
until it clips with bass boost
full on. So whatever the capabilities are, its going to smoke, right?
They like to have 600 watt amps for their cars, OK?

But a civilised old audiophile will usually want no more than 1 watt
average PO level per channel;
1 watt into speakers of 88dB/W/M will be too loud for most folks.

So the 10 watt PP amp will cope without exceeding its device dissipation
ratings and max current ratings.

Now let us suppose we have a well designed SET amp with a lone 300B
which makes a maximum
of say 8 watts into 8 ohms.

Loads either side of 8 ohms are limited by voltage swing limits or
current swing limits,
but if you plot a curve for PO vs load at 2% THD, you may find that
while 8 watts is possible into 8, maybe 5watts is possible into 4 or 10
ohms, and 3watts into 2 or 20 ohms.

Such a class A amp can be used with 2 ohms without clipping, ie, severe
distortion, and
it won't overheat because its already as hot as its ever going to get
while in pure class A, OK?

But the 2 ohm distortion at 2 watts will be worse than 8 watt into 8
ohms distortion, mainly because the
load isn't right for the tube, and complete fuctard has arranged for
such a rotten load to be used.

In a well designed SE amp, there is sufficient load matching coils on
the OPT to allow
good matching to any load you want from 1 ohm upwards.

Anyone stupid enough to expect a possible 20 watts from a lone 300B is a
fool.

So your arguments about SE amps being horrid all collapse because the
problems are not
in the technology, but within the ppl who use the technology.

If ever you want to have say 40 watt ability into some low load, then
design and build for that,
don't go running around telling folks SE amps are **** because they an't
cope and don't make increasing
PO as the load is reduced.

If you had an 8 watt SET load matched for 4 ohms instead of 8 ohms it
would make a nice coupla watts
into any load between 2 and 16 ohms, and it'd do what is expected by
most audiophiles.

If you are alergic to distortions creeping above 1% with wrong load
matching, then more NFB
would reduce it.

The 845 amps I am building have a 50 watt ability into 4 ohms, and
will provide ENOUGH pure class A power at 0.32 ohms Rout, wide BW and
low N&D
into any load between 2 at 20 ohms for 99% of audiophiles.

Your statements that SE amps won't cope well as loads become lower than
the rated load
is all BS.

If TWO 300B are used in pure class A you can get about 16 watts max, and
into whatever load
you want depending on the OPT turns count.
Above the load for 16 watts PURE class A the power falls off because of
rail voltage limitations.
But distortion also reduces, and damping factor increases.
Below the 16 watt pure class A load the power becomes class AB with
devices
beginning to switch off during wave cycles, and peak currents rising
above 2 x idle current.
Distortion increases, damping factor reduces.
Maximum clipping power increases as load is reduced, so that at 1/2 the
pure class A load,
you might get 25 watts, and so on.
But as load is further reduced the anode dissipation increases beyond
the maximum allowed,
and you might smoke a pair of 300B if you run the amp hard into 2 ohms
even well below clipping; there are dissipation limits
in PP tube amps just like in SS PP amps.

However, if you had the PP 300B amp set up so its max pure class A load
was for 4 ohms,
it would easily cope OK with 2 ohms, providing no fuctard was present at
the gain control
and hell bent on ruinations.

The only fair comparison to the above PP amps with anything SE could
only be made
if the SE amp had its class A power maximum at 8 ohms also, and also 16
watts, so you'd need TWO
parallel SE 300Bs, not just ONE, OK!

Then you'd find that listening to music at a low level well away from
clipping with either amp
with any load betaeen 2 and 20 ohms would not sound very different, and
the alleged
gross severe distortion from the SE amp is nowhere to be heard,
and you'd see that the Trevor Wilson
Theory Of SET Yuckiness has not the slightest relevance to any sensible
person.

I have been designing, building and selling SE amps of various types for
over 10 years, and the buyers reckon they sound better than PP amps, and
they have tried many, repeatedly.

In the best of my designs, the measured THD is no worse than many PP
designs
where that PP design has its rated AB PO equal to the max class A SE PO.

Pushing barrows full of spurious ideas given for free spoils the
Internet...

Patrick Turner.

[Tynan AgviÐr]

Eeyore wrote in
:



Trevor Wilson wrote:

I call people who imagine that SET amplifiers are high fidelity
deluded morons.




I tend to prefer SET amps in my own listening system. Every single amp
ive purchased in the past few years has been a SET design. For me,
listening is all about enjoyment...not pristine levels of
accuracy/distortion. This "clinical" approach is the very reason why 99
percent of recordings made since say...1990 or so sound like dog ass. DPA
Mics, Millennia Media Mic Amps,Sennheiser MKH 800(if I saw 5 of these
laying in their boxes brand new on the highway in front of my house I
would not take the time to pick them up..just awful! though many of my
colleagues laud them as being amazing(Micheal Bishop loves them too,
which should speak volumes as his engineering leaves very much to be
desired) Pyramix, SPHYNX converters,SONOMA, Sonodore,..aural hell.


all about enjoyment here. Perhaps if I were a scientist or design
engineer I would take more notice of paper specs..but as a sound engineer
and musician, music is my bread and butter..the day I stop enjoying it is
the day that i walk away from it. It makes me incredibly sad to see a
retailer such as Mr. Wilson bash listeners that really love music for
music's sake for choices in gear(esp. considering the fact that he is
supposed to be a "pro"). Live and let live, man. Accept others choices
and revel in your own.

by the way, Sir(Mr. Graham)..I sent you a couple emails though one of
them bounced back..if you could, email me to confirm reciept so I know I
am sending to the right spot. Thank you Sir.

[Peter Wieck]

On Jan 16, 4:35*am, "Iain Churches" wrote:

No Lowther is still going strong. *Andre, and also Dave L who
reads but does not post on RAT know much more about them
that I do.

http://www.lowtherloudspeakers.com/

I went to a Lowther convention a couple of years ago.
I took with me a CD of various pieces of music. Some
of what I heard was very much to my taste.

One has to understand that people are looking for a musical
experience. *This has nothing really to do with high fidelity in
the strictest sense of the term.

I think this explains most of the bones of contention around here. If
a system is seen to be an actual instrument vs. a neutral party
reproducing the source (whatever it is) as closely as possible, then
all sorts of aberrations are possible - in either direction.

a) Paper specifications become meaningless if the sound is pleasing.
c) The quality of the original recording-to-be-reproduce becomes
meaningless if the sound is pleasing.
d) Dynamic range and frequency response becomes meaningless if the
sound is pleasing.
e) THD, IMD, harmonics and other factors become meaningless if the
sound is pleasing.

And this is just fine. Absolutely just fine. As long as it is not
taken as revealed religion making non-believers necessarily heretics
and apostates. Some of us have difficulty with the physics of Lowther
horns, some of us have difficulty with the (relatively) high cost-per-
watt of SE designs - but writing for myself, I would not deny such
pleasures to others. I would (and do) object strenuously to having
that option shoved into my ears.

Yes. That is probably true. It's called brand loyalty.
It also extends to classical recording labels. *People buy the
Decca, or the EMI or the CBS version of a particular work.

Maybe. But much of the time they will be disappointed if they actually
listen to what they purchase. Even the best labels come up with
pretzels on occasion.

But, as people have more and more disposable income, the
interest in, how shall we call them, *"exotic" audio systems
is increasing. This is born out by the growing numbers of
bespoke tube amp builders turning out superbly crafted
products which cost a great deal of money. There seem to
be no shortage of customers for these.

Much of it is bragging-rights vs. actual audiophilia. Mine is bigger
and I can **** further! Or look what I am getting from 3 watts! I
would also argue the "superbly crafted" descriptive in more than a few
cases. High cost does not necessarily equal high quality or high
craftsmanship. Several offerings here have been proof-enough of that.

I for one, am very interested in the psychology behind the
purchase of a new "hi-end" audio system. *Maybe Trevor
can tell us sonething about this, even though he does not
sell tube amplifiers.

There are those who will purchase a Bentley or a Rolls or a Ferrari -
whatever - because that is what they want. There are those who do the
same because they can. First it is necessary to distinguish the former
from the latter. Those who purchase _anything_ because it is what they
want are to be at least respected for it whatever the reasons. Those
who purchase only because they can are sheep to be shorn - no more,
often less.

A dealer whom I know told me that what he calls
"cosmetics" account for 40% of the purchasing
decision, especially when choosing between two
amplifiers in a similar price range with similar performance
A tube amp certainly "looks" the part, if it meets the
criteria in other ways.

Only 40%? A touch of polished wood (inaudible) with silver or brass
trim (also inaudible), perhaps a bit of inlay or engraving will sell
more amps than absolute good sound all other things being equal.

Peter Wieck
Wyncote, PA

[Arny Krueger]

"Iain Churches" wrote in message
ti.fi
"John Byrns" wrote in message
...
In article
,
"Iain Churches" wrote:
"John Byrns" wrote in message
...
In article
,
"Iain Churches" wrote:

was matched.
The BBC did this too (see Morgan Jones, Valve
Amplifier 2nd Ed.page 452)
I was hoping that Graham would explain why this would
have been done.

Did the BBC prefer this impedance level for speakers? For example I see
that the LS3/4 monitoring speaker is 25 Ohms.

Yes it seems so. I am interested to know why.
I made the erroneous (?) assumption that better
damping was the objective.

Assuming that it was an erroneous assumption, only you
can tell us why you made it?

I thought (hoped) that Zo would remain the same, and so
the ratio of speaker to amplifier impedance might be
greatly improved.


Another thought is that" in the thinking of the time it
may have had to do with minimizing the interaction
between the speakers and the speaker "cables.

Possibly. Sadly, there are few designers left from that
era that we can ask.

One somtimes sees BBC spec Leak amps for sale, which
have become separated from the speakers they were designed
to drive. People buy them in auction without realising
that they have custom OPTs.

I doubt it, this is simply an example of Graham
opening his mouth before
putting his brain fully in gear. "Norton/Thevenin
equivalent ciruit analyis" is of little relevance in
understanding the reality of speaker damping and the
so called "damping factor.

Still, it would be of interest to have some discussion
on this point. It seems to be one of the stumbling
blocks of understanding in tube amps. I get the
impression that Graham seems to think it is unimportant in the greater
scheme of things. He may
well be right. But if so, why do SS designers seem to
attch so much importance to Zo, and criticise poor damping factor as
being one
of the major short comings of SET?

I don't have a clue why SS designers attach such
importance to the so called "damping factor".

Neither do I. But I am sure there is someone here who can
tell us.
I assume it is because it is a simple number
that has been sold to the public and makes for good
advertising copy. With any reasonable "damping factor",
of say 10 or better, the DC resistance of the speaker
voice coil completely dominates in determining the
electrical damping of the speaker, but this is a subtle
point that people don't' easily understand.

So you think that Zo = 0.8 Ohm is OK?

Depends on the minimum impedance of the speaker.

A good rule of thumb is that Zout + Z speaker line should be Speaker
DCR/30. Certainly by the time you are at DCR/10, an approximate 1 DB
frequency response variations is being imposed on the speaker.

Tests by Olson, or was it Tremaine, showed that people
were unable to detect an increase in DF above 12 so your figure
may well be very close to the mark.

I daresay that almost every test that relates to the sensitivity of human
perception to various technical variations like these has been redone since
the days of Olson and Tremaine.

Iain

[Trevor Wilson[_2_]]

"Eeyore" wrote in message
...


Trevor Wilson wrote:

"Eeyore" wrote

Emitter followers without loop-feedback aren't that great.

**Who said that a BJT amp required Emitter follower outputs?

What do you propose in their place ?

**The Sziklai type system seems to work well.


Trevor Wilson

[Arny Krueger]

"Iain Churches" wrote in message
ti.fi

Arny wrote:

There's no way you can show logically that a strategy of adding
randomly-chosen noise and distortion gets you closer to the original live
performance

But that's the whole point, Arny, with the exception of
classical and jazz recordings, there is no *live*
performance.

That's a common form of self-deceit that superannuated bigots tend to
indulge in.

Popular music is assembled track by track
(we call it musical brick-laying)

Similar techniques are sometimes used for jazz and classical works, and
billions of live recordings of popular and rock performances have been sold.

Intelligent people know that all generalizations are false, including this
one. ;-)

Tracks are added in
different acoustics in studio which may be continents
apart.

It all happens, regardless of the type of music. I know of no genre of
music that has not been recorded live.

There is no *original* So, (and this is the
crux of the whole matter) people are looking for a system
"which interprets the music of their choice in a manner which pleases
them"

The only universal constant is that a distributed recording is a very
definate thing that someone listened to over a monitor or mastering system,
adjusted in terms of mix and mastering or both, and approved for
distribution as it was heard by them.

So if you want to be pedantic Iain, and I know how desperately do want to
sound pedantic, it can be said that:

There's no way you can show logically that a strategy of adding
randomly-chosen noise and distortion gets you closer to the recording that
it was intended to be distributed and listened to.

[Arny Krueger]

"John Byrns" wrote in message

In article ,
"Arny Krueger" wrote:

"John Byrns" wrote in message

In article ,
Eeyore wrote:

Trevor Wilson wrote:

High fidelity meaning with great accuracy. NOT with
high distortion.


**Because any product which DELIBERATELY introduces
(audible) distortion is, by definition, not high
fidelity. It is something else.

Exactly so. 'High fidelity' has a specific meaning that
specifically excludes adding intentional and entirely
avoidable distortions..

What is the relevance of "High fidelity" in today's
audio scene?

The search for accuracy made it everything good that it
is.

Most, if not all, current recordings fail the
"High fidelity" test because of all the equalization,
compression, clipping, and etc. applied to them, along
with the microphone techniques used.

There's a lot of stuff, particularly in the classical
domain, that is recorded with a few mics and that's
about it.

However, accurate reproduction of highly-produced
recordings gets you closer to what the producers
intended.

I would think that to get the sound the producers
intended, you would not want an "accurate" system, you
would want a reproducing system identical in its effects
to the one they used while producing the recording, and
even that wouldn't work if others made changes later, as
in the CD "mastering" process.

With few exceptions, the systems that people use while producing and
mastering a recording were designed for a goodly measure of sonic accuracy.

Perhaps you or Iain can show us a requisition from a well-known music
production organization, Decca for example, for a large number of
highly-colored SET amplifiers driving say Lowther horn-loaded speakers,
intended to be used universally in-house for producing records.

[Arny Krueger]

"Iain Churches" wrote in message
ti.fi
"Arny Krueger" wrote in message
. ..
"John Byrns" wrote in message

In article ,
Eeyore wrote:

Trevor Wilson wrote:

High fidelity meaning with great accuracy. NOT with
high distortion.


**Because any product which DELIBERATELY introduces
(audible) distortion is, by definition, not high
fidelity. It is something else.

Exactly so. 'High fidelity' has a specific meaning that
specifically excludes adding intentional and entirely
avoidable distortions..

What is the relevance of "High fidelity" in today's
audio scene?

The search for accuracy made it everything good that it
is.
Most, if not all, current recordings fail the
"High fidelity" test because of all the equalization,
compression, clipping, and etc. applied to them, along
with the microphone techniques used.

There's a lot of stuff, particularly in the classical
domain, that is recorded with a few mics and that's
about it.

Indeed Arny. You give the impression it is a lot simpler
than it actually is.

No, I'm just avoiding the introduction of irrelevant complexity. I don't
think I need to produce a treatise in microphoning techniques every time I
mention the word microphone.

Neither do you specify what you mean
by "a few mics". There are actually very few topologies
using a few mics that actually work well. In addition,
they require considerable skill and experience in placing
to get the correct ratio of orchestra to ambience etc.

Given that you've never produced a recording all by yourself Iain, it is
likely that the art of choosing and placing microphones is more of a mystery
to you than I.

However, accurate reproduction of highly-produced
recordings gets you closer to what the producers
intended.

Hmm. I wonder, how can you know what the producer
intended?

Many ways that involve communicating with producers and reading and
listening to what producers say in various publications. Most of the
statements I've seen made is that in particular mastering systems, which are
used to perform final checks on sound quality, are usually chosen for their
sonic accuracy.


I can tell you, from having sat next to recording
producers on more sessions than I can remember, their
intention was to record a performance to do justice to
the intentions of the composer, the reproduction of which would give
pleasure to the
listener.

How do your producers know which of the myriad possible types of colorations
of consumer audio systems that their listeners prefer?

[Arny Krueger]

"Iain Churches" wrote in message
ti.fi

The expectations of a pop audience (who probably listen
mainly in their cars, or with iPod, are very
different to those who enjoy classical music..

So then Iain it is your claim that all car systems and iPod systems sound so
much alike that one can pre-color recordings so they sound best on them.

To make this believable Iain, please document the equalization curve that is
used to accomplish this.

[Arny Krueger]

"Eeyore" wrote in
message
Trevor Wilson wrote:

"John Byrns" wrote
"Trevor Wilson" wrote:

**Not by a long chalk. Graham and I dissagree about
the use of NFB in amplifiers.

I wouldn't have guessed in a million years that you and
Graham disagree about the use of NFB in amplifiers.
Which one of you is on which side of the issue?

**I have a preference for zero global NFB. Graham
prefers global NFB.

It's about the ONLY way you can make the output impedance
of a normally biased bipolar output stage behave itself
for one thing.

Emitter followers without loop-feedback aren't that great.

Emitter followers are not all that bad. Generally, emitter followers have
the lowest output impedance of all possible configurations of one
transistor. All of the configurations of two transistors that I know of that
have low output impedance include something like an emitter follower.

The reason for this is the fact that emitter followers inherently have a lot
of negative feedback. So much so that their voltage gain is always less than
1.000.